Low-light viewing systems are widely used in the military to provide soldiers, aviators and sailors with the ability to view objects at night or during other low-light conditions. As a result, many low-light viewing devices are currently being manufactured according to exacting military specifications and designs. Similarly, many such low-light devices are being manufactured for specific military applications, such as part of the sights of various weapons or as part of goggle assemblies that attach to an aviator's or soldier's helmet. However, many of the present low-light viewing devices currently being manufactured are neither affordable nor easily adapted to non-military uses.
Low-light viewing devices fall into several broad categories, including: (1) image intensified products, (2) thermal imaging products, and (3) charge-coupled device (CCD) and complementary metal-oxide-semiconductor (CMOS) low-light cameras. The image intensified and thermal imaging devices are often found in the military, law enforcement, fire fighting, and consumer markets. In recent years a number of low-light viewing devices have been introduced into the consumer market, but are often of poor quality and/or offer the user limited capabilities.
Image intensified low-light viewing devices tend to be very expensive and require sophisticated, heavy lenses to produce long range images. Image intensified devices are also quite prone to damage if used in high-light situations. This characteristic renders such products virtually useless in most urban areas. Moreover, due to excessive cost, thermal imaging devices have not been widely accepted.
Low-light CCD cameras are commonly employed in security applications. In recent years, cell phone technology, as well as a tremendous surge in the application of cameras in the security business, has provided for very inexpensive cameras. Low-light CCD cameras are designed to be sensitive at a wavelength in the electromagnetic spectrum that is invisible to human beings, making these cameras very effective in low-light conditions, particularly if active infrared (IR) illumination is employed.
Devices that utilize active IR illumination often utilize integral LEDs to illuminate dark scenes. Most digital low-light viewing devices currently on the market utilize fixed-focus lenses which must be manually adjusted and are active devices, i.e., providing IR illumination to assist in detection, which causes the devices to consume power quickly.
The aforementioned devices are deficient in several respects, precluding practical use in both commercial arenas and by the military and law enforcement agencies. Such devices tend to be both heavy and fragile, are unable to withstand the shock of impact and wear and tear caused by regular military or law enforcement use, and are easily permeated by water or moisture that can render them inaccurate or even unusable.
Additionally, such devices generally have fixed magnification that allow the user to detect objects, but lack variable magification capabilities that allow the user to recognize and identify objects once detected. These devices also tend to have relatively short ranges, are bulky, are not ergonomic in design, and lack simplified user controls. Moreover, such devices can be quite costly, often requiring proprietary components and elaborate assembly techniques, making them impractical for widespread military or law enforcement use.
Accordingly, there exists a need for a ruggedized, handheld digital low-light viewing device well suited for military, law enforcement, security and first responder use, with variable magnification (zoom) capabilities, which can be operated with one hand, is lightweight and waterproof, and which contains additional features not presently available in prior devices and operable in conjunction with current low-light sensor technology.